The invention relates to a moulding arrangement for an injection-moulding machine,                the injection moulding arrangement is configured for moulding at least one article composed of components of at least two different materials,        the injection moulding arrangement comprises an injection mould having a movable mould half and a stationary mould half, which mould halves in a closed position of the injection mould define at least two cavities for injecting the different materials for the respective components moulded at each stroke of an injection-moulding machine,        in the closed position of the injection mould the at least two cavities correspond to the shape of one or more of the components of the at least one article,        the at least two cavities are arranged at angular distance from each other,        the at least two cavities are arranged at equal distances from a central axis of the injection mould,        parts of the at least two cavities are formed in a separately movable section of the movable mould half of the injection mould, and        the injection moulding arrangement comprises an operation part for in an open position of the injection mould displacing said separately movable section to-and-fro between an extended position and a non-extended position.        
The invention also relates to a method for by means of the injection moulding arrangement producing articles composed of components made of different materials.
Within the context of the present invention the term “different materials” includes materials, which have the same or different physical properties, chemical properties and/or different colours. These materials can e.g. be a plastic material, such as a thermoplastic polymer. So two materials with different or same properties can be combined into articles with delicate and complicated structures, however moulding complicated articles of one of the same material but requiring several separate moulding steps to achieve the finished article are also foreseen within the scope of the present invention.
In some cases the design of an article requires that the article have more different colours. In other cases an article is made of two or more materials to improve any or all of e.g. usability, user friendliness, quality, property, functionality, and aesthetics of the article. One of the materials can for example be abrasion-proofed, antislip or rubbery, to respectively confer abrasion resistance, antislip or friction properties to the final article. At the same time any of the included material can have another colour than the other materials.
An injection mould usually consists of a movable mould half and a stationary mould half. The movable mould half is directly or indirectly fastened to a movable clamping plate of an injection-moulding machine. The stationary mould half is directly or indirectly fastened to a stationary clamping plate of the injection-moulding machine.
Cavities of opposite mould halves together define the shape of the articles to be moulded in the closed mould. These cavities are typically machined in plates.
In a known method for e.g. producing an article of two components made of each their material a first component is moulded in a first cavity of a mould clamped in an injection-moulding machine. Then the first component manually or by means of a robot is transferred to a second cavity of the injection mould where the second material is injected onto or at the first component in a second operation cycle.
Carrying out this method for producing articles of more components made of different materials is however costly and time-consuming. Moreover this method requires relatively large investments in machinery and tools.
An attempt to overcome these problems is known from the patent specification GB 1 392 074 describing a method for in one operation cycle producing an article consisting of two components made of each their material in one mould. One side of the surface of the stationary mould half is formed with cavity halves for a number of first components while the other side of the surface symmetrically is formed with cavity halves for the same number of finished articles whereby the movable mould halves is equipped with corresponding mould cores. A transporting plate, which is both axially and turnable displaceable by means of a drive shaft, is placed between the two mould halves. The transporting plate is formed with bores for allowing the cores to enter the respective cavities in the stationary mould half during a shot. Opening the injection mould and retracting the cores from the transporting plate and the transporting plate from the stationary mould results in that the finished articles are falling out of their cavity halves in the stationary mould half while the injection moulded first components are pulled out of their cavities by being adhered to the transporting plate. The transporting plate is then turned 180° whereby the injection moulded first components are brought into position in front of the cavities for the finished articles. When being closed the injection mould is ready again for moulding a number of both first components and finished articles.
This known injection mould arrangement suffer however of the serious drawback of being limited to be used for only moulding cup-formed articles, since this know arrangement cannot function without such cores. Moreover, the transverse extension of the transporting plate is relatively large since said extension mainly corresponds to the extension of the injection mould. The transporting plate therefore has a relatively large moment of inertia, which implies that the time for turning the transporting plate for each operation cycle needs to be relatively large, and the production capacity therefore corresponding little. The arrangement can moreover hardly be converted to produce different products, at least only by replacing large parts of the arrangement. Moreover, the functioning of the mechanism for axially displacing and turning the transporting plate is both complicated and unsteady, especially because the injection moulded first components do not adhere securely to the transporting plate during the retracing and turning operation of this transporting plate.
From German patent document DE 4 243 293 is known a corresponding injection moulding arrangement which however suffers from substantially the same disadvantages and drawbacks as mentioned above in relation to the injection moulding method of GB 1 392 074.
DE 4 243 293 relates to a moulding arrangement of the kind having an injection mould for manufacturing plastic toothbrush brushes. The injection mould comprises a stationary and fixed mould plate, an opposite moveable ejector mould plate and a rotary part together defining three angularly displaced moulding positions for injection of three different plastic materials in three angularly displaced substantially identical moulding cavities. In each position an injection unit injects a respective liquid molten plastic material through a sprue bushing via a channel and a nozzle into the respective mould cavities putting additional layers around the tooth brush. The rotary part holds the head part of the toothbrush brushes when the moveable plate and the stationary plate are moved apart so that the toothbrushes can be rotated to a next injection position by means of the shaft of the rotary part or be cooled and ejected at the end of the injection operation cycle. The rotary part has arms with pins extending into slots in the elongate toothbrush body to hold this body stiff during rotation when the injection mould plates are spaced apart. If no pins were provided, the toothbrushes would bend or even drop to the bottom of the injection moulding arrangement during rotation of the rotary part. The pins leave holes in the toothbrush. Such holes are undesired and not possible to include in many other moulded articles. So this known moulding arrangement is not intended nor suited for moulding other objects than simple toothbrushes. Adding extra parts to a basic body of more complex structure is not foreseen.
A further major disadvantage consist in that injection takes place from the stationary mould plate directly onto the tooth brush shaft in each moulding step, which inevitable leaves disfiguring moulding residues, such as moulding fins, moulding flashes, moulding burs or moulding seams, protruding from the tooth brush towards the stationary moulding plate thus being a potential obstacle for the subsequent moulding step. Such moulding residues can be in the way when turning a half-finished moulded toothbrush to its next moulding position, and the injection moulding plates need a substantial clearance from each other to allow the rotary part to rotate. Moreover, when the injection moulding plates are joined again for adding an extra layer around the toothbrush's elongate shaft that protrudes from the rotary part the next moulding cavity is not able to take the residue made in the earlier moulding step into account.